Abstract

The control over the distribution of magnetic ions in a host is crucial for the functionality of magnetically dopedsemiconductors. Herein, (Co,Cr)-codoped ZnO shows a possibility of Cr-codoping engineering in mediating the distribution of magnetic Co ions via manipulating the charge state of the Co ions. The x-rayabsorption fine structure analyses at -edge indicate that a secondary phase of metallic Co clusters is formed in the film. However, Cr-codoping suppresses the formation of Co clusters, so that all doped Co ions occupy the substitutional sites in ZnO. The ability of Cr in mediating Co distribution, as revealed by first-principles calculations, arises from the strong hybridization between the states and the donor band induced by substitutional Cr ions, which facilitates the charge transfer from the donor band to the states, changes the charge state of Co ions and modifies the electrostatic interactions among Co ions.

Received 04 June 2010Accepted 02 July 2010Published online 27 July 2010

Acknowledgments:

This work was supported by the National Natural Science Foundation of China (Grant Nos. 10635060, 10979041, 10975140, 10979044, and 10725522), and Knowledge Innovative Program of The Chinese Academy of Sciences (Grant No. KJCX2-YW-N40).